Solid Solution Hardening and Mechanical Properties Variations in α Cu-Al Single Crystals

Author(s):  
Jacques Vergnol ◽  
Jean-Pierre Villain
2020 ◽  
Vol 326 ◽  
pp. 06004
Author(s):  
T.Ha Nguyen ◽  
Ram Song ◽  
Yohei Harada ◽  
Shinji Muraishi ◽  
Shinji Kumai ◽  
...  

Al-Mn based alloys with high-manganese content are expected to have improved mechanical properties due to solid solution hardening and/or dispersion hardening. However, the increase of Mn solubility of the alloy is difficult by using the conventional DC casting. In order to solve this problem, in the present study, we focused on the twin-roll casting method which is characterized by high cooling rates. Several kinds of high Mn-containing Al-Mn-Si alloy strips were fabricated by using a vertical-type high-speed twin-roll caster equipped with a pair of water-cooled copper rolls. Direct temperature measurement of the liquid melt during the casting was also performed. The alloy strips of various compositions containing up to 4 Mn and 2 Si (wt%) were successfully obtained. By observing the microstructure of the cross section of the strip, we found the characteristic solidified structure. The solidified structure consisted of three layers. Two solidified shells with a columnar dendrite structure grew from the roll surfaces toward the strip center. In the mid-thickness region, the band structure consisting of equiaxed dendrites and globular grains was observed between the solidified shells. Very fine primary particles were observed in the matrix near the strip surface, while, relatively coarse particles with blocky and needle-like shape were observed in the central band of the as-cast strip. The electric conductivity measurement was performed for the as-cast strips. Mn solubility in Al matrix was estimated from the obtained values. The estimated Mn solubility in the Al-2Mn-xSi strips was between 1.5 ~ 1.8wt% Mn. It was over 1.43wt%Mn for the Al-4Mn-xSi strips. We found that the Mn solubility of the as-cast strips was considerably high. The strips were cold-rolled to the sheets and then annealed at various conditions. They were subjected to the tensile tests, and the effects of solid solution hardening and dispersion hardening are discussed.


1996 ◽  
Vol 460 ◽  
Author(s):  
A. L. R. Sabariz ◽  
G. Taylor

ABSTRACTThe intermetallic compound, RuAl with B2 CsCl type structure, has been shown to possess room-temperature toughness and plasticity. NiAl also forms a B2 compound and it is claimed that a pseudo-binary compound, (Ru,Ni)Al, may be formed because the difference in lattice parameter between the two binary phases is slight. In this work a study has been made of the mechanical properties of some polycrystalline compounds, across the RuAl-(Ru,Ni)Al pseudo-binary, prepared from high-purity elemental powders. Compressive yield stresses were measured between room-temperature and 900°C, and the mechanisms of plastic flow are discussed in relation to the dislocation structures observed by TEM. Hot-microhardness tests were made to provide an indication of the effect of solid-solution hardening.


1979 ◽  
Vol 53 (2) ◽  
pp. K143-K145 ◽  
Author(s):  
P. Lukáč ◽  
Z. Trojanová

1999 ◽  
Vol 121 (2) ◽  
pp. 172-177 ◽  
Author(s):  
C. L. Briant ◽  
D. H. Lassila

This paper reports a study of the mechanical behavior of Ta-W alloys. The results show that tungsten additions increase the yield strength and the rate of work hardening of tantalum. These additions also cause a change in the deformed microstructure from one that is primarily cellular to one that consists mostly of dislocation tangles. It is proposed that the increase in yield strength arises from solid solution hardening and that the increase in the work hardening can be correlated with an increase in the density and arrangement of dislocations present in the material.


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